package net.minecraft.entity.ai.goal;

import net.minecraft.entity.LivingEntity;
import net.minecraft.entity.ai.TargetPredicate;
import net.minecraft.entity.ai.pathing.Path;
import net.minecraft.entity.ai.pathing.PathNode;
import net.minecraft.entity.attribute.EntityAttributes;
import net.minecraft.entity.mob.MobEntity;
import net.minecraft.scoreboard.AbstractTeam;
import org.jetbrains.annotations.Nullable;

/**
 * A goal that maintains the target of a mob entity. If the goal stops,
 * such as because the target is not valid, the target is removed from
 * the owner mob.
 * 
 * <p>Compared to other goals, this goal and its subclasses are added
 * to the {@linkplain MobEntity#targetSelector target} than the regular
 * goal selector, and should use the {@link Goal.Control#TARGET}
 * control if it sets the owner's target.
 */
public abstract class TrackTargetGoal extends Goal {
	private static final int UNSET = 0;
	private static final int CAN_TRACK = 1;
	private static final int CANNOT_TRACK = 2;
	protected final MobEntity mob;
	protected final boolean checkVisibility;
	private final boolean checkCanNavigate;
	private int canNavigateFlag;
	private int checkCanNavigateCooldown;
	private int timeWithoutVisibility;
	@Nullable
	protected LivingEntity target;
	protected int maxTimeWithoutVisibility = 60;

	public TrackTargetGoal(MobEntity mob, boolean checkVisibility) {
		this(mob, checkVisibility, false);
	}

	public TrackTargetGoal(MobEntity mob, boolean checkVisibility, boolean checkNavigable) {
		this.mob = mob;
		this.checkVisibility = checkVisibility;
		this.checkCanNavigate = checkNavigable;
	}

	@Override
	public boolean shouldContinue() {
		LivingEntity livingEntity = this.mob.getTarget();
		if (livingEntity == null) {
			livingEntity = this.target;
		}

		if (livingEntity == null) {
			return false;
		} else if (!this.mob.canTarget(livingEntity)) {
			return false;
		} else {
			AbstractTeam abstractTeam = this.mob.getScoreboardTeam();
			AbstractTeam abstractTeam2 = livingEntity.getScoreboardTeam();
			if (abstractTeam != null && abstractTeam2 == abstractTeam) {
				return false;
			} else {
				double d = this.getFollowRange();
				if (this.mob.squaredDistanceTo(livingEntity) > d * d) {
					return false;
				} else {
					if (this.checkVisibility) {
						if (this.mob.getVisibilityCache().canSee(livingEntity)) {
							this.timeWithoutVisibility = 0;
						} else if (++this.timeWithoutVisibility > toGoalTicks(this.maxTimeWithoutVisibility)) {
							return false;
						}
					}

					this.mob.setTarget(livingEntity);
					return true;
				}
			}
		}
	}

	protected double getFollowRange() {
		return this.mob.getAttributeValue(EntityAttributes.FOLLOW_RANGE);
	}

	@Override
	public void start() {
		this.canNavigateFlag = 0;
		this.checkCanNavigateCooldown = 0;
		this.timeWithoutVisibility = 0;
	}

	@Override
	public void stop() {
		this.mob.setTarget(null);
		this.target = null;
	}

	protected boolean canTrack(@Nullable LivingEntity target, TargetPredicate targetPredicate) {
		if (target == null) {
			return false;
		} else if (!targetPredicate.test(getServerWorld(this.mob), this.mob, target)) {
			return false;
		} else if (!this.mob.isInPositionTargetRange(target.getBlockPos())) {
			return false;
		} else {
			if (this.checkCanNavigate) {
				if (--this.checkCanNavigateCooldown <= 0) {
					this.canNavigateFlag = 0;
				}

				if (this.canNavigateFlag == 0) {
					this.canNavigateFlag = this.canNavigateToEntity(target) ? 1 : 2;
				}

				if (this.canNavigateFlag == 2) {
					return false;
				}
			}

			return true;
		}
	}

	private boolean canNavigateToEntity(LivingEntity entity) {
		this.checkCanNavigateCooldown = toGoalTicks(10 + this.mob.getRandom().nextInt(5));
		Path path = this.mob.getNavigation().findPathTo(entity, 0);
		if (path == null) {
			return false;
		} else {
			PathNode pathNode = path.getEnd();
			if (pathNode == null) {
				return false;
			} else {
				int i = pathNode.x - entity.getBlockX();
				int j = pathNode.z - entity.getBlockZ();
				return i * i + j * j <= 2.25;
			}
		}
	}

	public TrackTargetGoal setMaxTimeWithoutVisibility(int time) {
		this.maxTimeWithoutVisibility = time;
		return this;
	}
}
